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The results of 20 years of monitoring of the evolution of the radio flux density from SN1987A are described. Following a prompt radio outburst, no radio flux was detectable from SN1987A until 1990. Since then, there has been a gradual increase in the flux density at all frequencies (the 1.4 GHz flux density at the beginning of 2007 was 0.32 Jy) and a gradual flattening of its spectral index to the current value of α = −0.75 (S ∝ vα). The remnant is now bright enough to detect, via HI absorption, components of the foreground interstellar medium not seen since ultraviolet observations shortly after the explosion. Nevertheless, SN1987A remains spectacularly underluminous in the radio compared with more distant radio supernovae detected by existing radio telescopes.

This paper describes some of the polarimetry done with the Australia Telescope Compact Array (ATCA). Comparatively low and stable instrumental polarization allows high quality polarimetric images to be formed. The instrument has proven particularly successful in studying low level circular polarization. The instrument has also proven itself excellent for widefield imaging of galactic polarization. We consider some of the techniques used in widefield polarimetry of an interferometer.

AMiBA is a 90 GHz interferometric array of the ASIAA (Academia Sinica, Institue of Astronomy and Astrophysics). It will make a detailed study of the polarization of the CMB anisotropy; it will also undertake a survey of Sunyaev-Zel’dovich clusters. It is under construction at present, with an expected completion date of late 2003.